Improvement in rock-drills



y of Fitchburg,

mode of operationof the drill patented tome .machine is` made I' very simple.V and --cei-npa'ct,

, levers within them'w'hichmove the valve, and,

`-the manner of constructing and arranging PATENT OFFICE.

c" lianes :Bum-luren, 0F TFITGHBURG, MASSACHUSETTS.

To all who'mlz't'may'concerne l Be it known thatI, CHARLES -BURLE1GH,

in the county oi' Worcester and State of Massachusetts, haveinvented 'cirev tain Improvements i'n'v Rbck-Drillsiof 'which'V the following is a specification if My' inventions relate to' thev Construction and arrangementot' Several efth'esubordinate parts of a" rock-drill, having the general- November 27, 1866; No.=59,'060, by whichlthej and better adapted to work in coninedspaces and for drilling small' holes, 'as in'm'ining .galleries, and which, for disti'nc'stion, I call a f stopingdrill..

Thev rst part of my'invention relates to the manner of constructl'n the mechanism for working? the valve: which admits the Steainfor air tothe piston, andcon-l sists in forming the steamer 'air passages, at each end of thev cylinder: sof as' to receive the in combination therewith, the arrangement of the annular cams which operatesaid levers upon the ends of a long piston-head, so that the mechanism for moving the valve is inclosed within the air-passages.

The second part of my invention relates to the back cylinder-head, in relation to the other parts of the machine, by which the machine is considerablyv shortened as 'compared with the machineshown and described in 'my .aforesaid patent No. 59,960, While retaining an equal length oi' the stroke, and of the wearing-surfaces of the piston-bar, and consists in forming the back cylinder-head with a closed bearing for the back end of the piston-bar and a recess for the turning-ratchet, so that no part of the operative mechanism passes through it,

The third part of my inventionrelates to the construction of the valve mechanism so that it may be operated by hand when necessary, which will be described.

In the drawings, Figure 1 isa 'plan ofmy machine with apart in section to show the construction of the valve-mechanism; and Fig. 24 is a' sectional elevation through the 'g` and arranging.

center of the machine. A is the frame or bed-plate oi' the machine. B isthe cylinder; C, the piston; D, the piston-bar; E, the drillchuck F, the front cylindenhead F', the back cylinder-head; G, the turning-ratchet; yH, the pawl for the sameyI, the spring which holds lthe pa'wl to-the ratchet, J J the helical grooves in the piston-bar, by which thedrill and piston1 and'parts connected there with, are turned; and K is the feeding-Screw, by which fthe drin is fed forward..

The mode of operation of these parts is Asubstantially the `same as that ot' the corre- 'spending part'sgasrdescribed in my aforesaid lpatent No. 59,960, vwith certain modifications qt' construction, which will be hereafter more particularly described. L is the valve which admits the air or steam to the piston, and L' is' the valve-rod. M M are two bent levers for working che 'val'veby means ot`A the annu- -lar cam-surfaces c c upon the vends oi' the piston. These levers areplaced in the passages or ports which conductthe air from the Iva ve in-to and out of the cylinder and work upon the axes l. The outer arms of the levers work in suitable bearings in the valverod L', as shown, near each end 5 and the inner ends m m of the' levers are made in the form of curvedinclines, .which project within the bore of the cylinder near each end, when the valve is atthat end of itsv stroke so that as the piston moves to that end of the cylinder the rounded-end of the 'piston comes in contact with it and' pushes it laterally outward, which throws the valve to the opposite ,end ot' its stroke, and opens the port, and by the saine action moves thel other lever so that its inner end will project within the cylinder in the same manner. The valve L works in the'central compartment. ot the valve-casing N, in the usual way, and in the two cuter compartments N the levers M Work, and connect with each end ot' the valve-rod, as is Shown. Where the valve-rod passes throughv the partitions between the compartments, the joints are made tight by packing, at n, for

which recesses are made inthe metal to receive it, as shown; or the joint around the valve-rod may be made tight in any other suitable. manner. The outer compartments of the valve-casing are in direct connection with the cylinder-ports. The back end of the valve rod extends through a stuffing-box, O, and its outer end is, provided with a. slot, P, through whichthe lever Q passes, as seen more clearly in Fig. 2. This lever has its fulcrum at R, and is held in a centra-l position by aleafspring, S, which bears against the square end ot' it, as shown. The slot Pis made of suicient length to permit the valve-rod to move irs entire stroke without the ends of the slot coming in contact with the lever. The purpose of this lever Q. is to work the valve by hand to start the machine in an obvious manneinV Thepiston-head'O is made long and has the packingring C at the middle, and each end of the same,'c c, is made long en ough to reach past the acting faces of the levers M, while the packing-ring remains uncovered by the port or opening in theI cylinder in which the levers'M work. The ends cc of the pis- ,ton-head are -rounded so as to work properly with the levers M, in substantially the same.

way that the annular cam or projection Works, which is shown and. described in my'aforesaid patent No. 59,960. The back end ot the piston-bar D works in a long bearing, f, that is formed uponthe back cylinder-head F', as

shown, and fits nicely therein. In the sur- 'ace ot the rod are formed four helical grooves in`which two splines work, which are fixed in the ratchet G, upon opposite sides of the piston-bar. This arrangement ot' the ratchet and splines and helical grooves operates in the same way as in my aforesaid patent. The other two helical grooves are similar to these, and serve as' por ts to admit the air or steam to the back end of the piston-bar, and when theotber grooves are too much Worn for use these two grooves may be brought into use instead, and the other grooves serve as ports. As this part of themachine'is subject to much wear, this construction gives it twice the dn rability. Six or more grooves might be used in the same way, but this would probably remove too much of the outside bearing surface of the piston-bar, but I have tried four grooves with perfect success. T is a buffer of indiarubber to cushion the backward stroke of the pistonbar.

By this arrangment all the operative parts ot' the machine are entirely inclosed within the casing of the machine, excepting-the work- 'ing end of the drill-bar, tov which the drill is Y attached, and the pressure of the air or steam is exerted upon the entire area of the piston at the back end, while the bearing at the baclr end of the piston-bar is preserved andmade very efficient, which is a matter of much importance in drilling horizontally, :where the extended drill is supportedV entirely by the piston-bar, and without the back bearin g the piston and bore of the cylinder will-be very soon worn out of shape.` In thedrawings the V machine shown is fed forward by the hand of the operator, by means of the crank U, upon the feeding-screw K.

The operation of the machine is believed to be obvious without further descriptiou'of it.

What I claim is- 1. The'combination of the bent levers M, with the annular carn-surfaces o c on the piston, said levers moving laterally thereto, as

described, andthe valve, where said levers are arranged within the air-passages which lead fromthe valve into the cylinder, substantially as described.

2. The closed back cylinder head formed with a closed bearing for the back end of the pistonbar, and a recess for Y the turningratchet, constructed and operating subst-an# stantially as described.

3. The lever Q provided with a spring, S, to hold the same iu a central position in combination with the valve-rod having an elongated slot P, substantially as described.

Witnesses:

H.. A. WILLIS, WM. C. HIBBARD.

CHARLES BURLEIGrH.` A 

